Although activity on the World-Wide Web has burgeoned over the past year or more, the images available over the Web are educationally inferior to those available in stand-alone programs. In particular, current implementations of Web-based images do not give effective feedback to users about regions within images. To extend the reach of medical libraries into medical education, we propose to construct a novel environment for distributing medically educational images to students, residents, and practicing physicians. In so doing, we shall construct Web-based functionality that can supersede image mapping on the World-Wide Web. We have spent the last year developing an extensive Web-based campus- wide information system, with the capacity and support to deliver image databases, or imagebases. We have also constructed platform-specific stand-alone application, called OverLayer, that can present images with overlays-regions of an image with associated text. We call an image with such overlays a slide. OverLayer is designed for searching, self- testing, and a variety of other activities that have traditionally been associated with stand-alone programs of high educational quality. We have used this program successfully in the context of a stand-alone Histology imagebase. In this proposal, we are aiming to fill the gap between the stand-alone and World-Wide Web polarities: We propose to develop a platform- independent, Java-based environment for the creation, distribution, and viewing of such teaching slides. To test the concept of Web-based slides for education, we propose to create a library of digital slides for each of the years of medical school-Histology (first year), Pathology (second year), and Gastroenterology (clinical years-thus covering the entire medical- school curriculum, and allowing us to evaluate the usefulness of this capability across the curriculum. These images will be distributed over InfoNet, our campus-wide information system, and will be used by students by residents, attendings, and practitioners who are part of our community health information network wherever they may be (just-in- time learning). We shall evaluate our success by use statistics logged by our server, as well as by surveys of our different users. With this experience as a basis, we can decide how to go forward to other medical-educational needs, such as specialty continuing education. Our model of Web-based image publishing is designed for use at other institutions and we hope to distribute OverLayer widely. In summary, we propose to enroll the resources of the Library in distributing educationally useful images, using a novel, generalizable tool yoked to the World-Wide Web.